From: "Opensource [Anthony Olech]" <anthony.olech.opensource@diasemi.com>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>,
        "Opensource [Anthony Olech]" <anthony.olech.opensource@diasemi.com>
CC: LKML <linux-kernel@vger.kernel.org>,
        David Dajun Chen <david.chen@diasemi.com>
Subject: RE: [PATCH] regmap-irq: allow auto-allocated IRQs to be mapped
Thread-Topic: [PATCH] regmap-irq: allow auto-allocated IRQs to be mapped
Thread-Index: AQHNckG72kyxY08IiEqTgpBfEDN7qZdONpdAgAAe5ICAABLO8IAAHywAgAEQD0A=
Date: Wed, 8 Aug 2012 08:30:07 +0000
Message-ID: <24DF37198A1E704D9811D8F72B87EB51032C3DBB@NB-EX-MBX02.diasemi.com>
References: <201208020805.q72858Yj003147@latitude.olech.com>
 <20120804105424.GB10523@opensource.wolfsonmicro.com>
 <24DF37198A1E704D9811D8F72B87EB51032C3B7E@NB-EX-MBX02.diasemi.com>
 <20120807140311.GH16861@opensource.wolfsonmicro.com>
 <24DF37198A1E704D9811D8F72B87EB51032C3C2A@NB-EX-MBX02.diasemi.com>
 <20120807170204.GU16861@opensource.wolfsonmicro.com>
In-Reply-To: <20120807170204.GU16861@opensource.wolfsonmicro.com>
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> -----Original Message-----
> From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com]
> Sent: 07 August 2012 18:02
> To: Opensource [Anthony Olech]
> Cc: LKML; David Dajun Chen
> Subject: Re: [PATCH] regmap-irq: allow auto-allocated IRQs to be mapped
> On Tue, Aug 07, 2012 at 02:37:37PM +0000, Opensource [Anthony Olech]
> wrote: 
> > > The bottom line here is that if your driver requires a dynamically
> > > allocated legacy domain it is broken.
> > I am trying to use the latest REGMAP API, and I do not understand why
> > you say the DSA9058 driver "requires" a dynamically allocated legacy
> domain.
> If you care if you got a linear or a legacy domain then that shows you're reyling
> on having a legacy domain (indeed, my statement above should've been
> stronger - if anything in the driver itself cares if it's got a linear or a legacy
> domain the driver is buggy).
> > Surely the virtual IRQs that the PMIC component drivers use must be
> > dynamically allocated. It is only the single GPIO line designated as
> > an interrupt line in the machne drivert that is fixed by the hardware.
> > That surely means the "irq_base" parameter to regmap_add_irq_chip()
> > must be set to "-1". What else could it be set to??
> If the driver doesn't have any inputs which could be used as an interrupt by
> another device then it should be set to -1, yes, and nothing in the code should
> ever care how the specific virq values are related to each other.
> If the driver does support another device using it as an interrupt controller then
> unfortunately for non-DT systems platform data would need to configure an
> irq_base so that the interrupt can be supplied to whatever the other device is
> but in all other circumstances it should be set to -1.
> > I am beginning to suspect that I have misunderstood something. The
> > regmap-irq API seemed taylor-made for our PMIC with one real h/w
> > interrupt line with several PMIC chip irq sources controlled by a set
> > of registers that seemed to slot into the "regmap_add_irq_chip" struct
> > perfectly. Why should that set of virtual irqs be given a specific base??
> It shouldn't, this is what I'm saying.  The IRQs shouldn't have a base at all and
> should instead be using a linear domain (which doesn't have a base but instead
> maps each IRQ on demand).  What your patch does is to stop that happening
> and instead always allocate a legacy domain even when linear is OK.
> It sounds like your code to allocate the IRQs is fine but the code using the IRQs
> is buggy as it's relying on the linear domain.

Thanks Mark, now we are getting somewhere - it must be my use of the IRQ domain
IRQs is wrong. There are exactly 3 mfd drivers that specify a base of '-1', namely:
	palmas.c, 88pm805.c, arizona-irq.c
so I will examine how they use the IRQs

thanks for your help
Tony Olech
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